OAKLAND — The managing director of a Walnut Creek investment firm was arrested Thursday on charges that he was defrauding his company’s lenders, prosecutors said Monday.

Stephen B. Lopez, 57, of Lafayette, was charged with mail fraud, wire fraud and money laundering after he reportedly misrepresented his firm’s ownership interests in various companies, properties and oil wells and used the fraudulent profits to pay off personal debt, according to Melinda Haag, U.S. Attorney for the Northern District of California.

Lopez solicited loans on behalf of Lighthorse Ventures LLC, a Walnut Creek-based private equity investment company for which he was managing director, Haag said. Lopez promised a return of 10 to 12 percent per year, and overvalued and misrepresented the entities owned by Lighthorse, she added.

Lopez did not tell prospective lenders that he had failed to return the principal and interest to the majority of his lenders, and that he would soon be required to make a final payment of $600,000 to Lonestar Trust as a result of a civil settlement agreement with his former clients, Haag said. The indictment also alleged that he used money paid to Lighthorse to pay a personal debt of $600,000 owed to clients, and to make a $50,000 payment to a consultant.

Lopez appeared Friday before a magistrate judge in San Francisco and was released on a $100,000 bond, Haag said. If convicted, he faces a maximum sentence of 20 years imprisonment and a $250,000 fine for each count of mail and wire fraud, and 10 years in prison and a $250,000 fine for money laundering.